10 Fluid Residence Time:

Several authors have characterized ground-water flow in the Cape Fear interval (Aucott and Speiran, 1985; Miller and others, 1986; Aucott, 1988; Miller, 1990). A number of authors determined that the deep aquifers directly below the coast is a marine/terrestrial ground-water interface zone in which waters tend to be stagnant. Miller and others (1986; their fig. 5) showed that the NA+ concentrations increase with distance along the aquifer flow path, and several authors showed that the Cape Fear aquifer in southeastern South Carolina contains relatively high concentrations of NA+ (Miller and others, 1986; Miller, 1990). On the basis of these data, we conclude that residence times in the Cape Fear aquifer of southeastern South Carolina are long, and may be as much as 5,000 yr.